1. Field
Various embodiments relate to optical communication technology, and more particularly, an optical transceiver based on a high-performance optical interface.
2. Description of the Related Art
In general, an optical transceiver converts an electrical signal into an optical signal or converts an optical signal into an electrical signal between an optical cable coupled to an optical communication network and a device for transmitting or receiving data. Since such an optical transceiver has a long transmission distance and a high transmission speed, the optical transceiver is used for high-speed large-capacity data communications.
The optical transceiver includes an optical transmitter and an optical receiver.
The optical transmitter is coupled to a laser diode for converting an electrical signal into an optical signal, and includes a laser diode driving circuit for driving the laser diode. The laser diode driving circuit of the optical transmitter has a differential structure, but an output terminal of the laser diode driving circuit, which is connected to the laser diode, has a single-ended structure.
Therefore, the optical transmitter may be vulnerable to a supply voltage fluctuation, a substrate noise, or the like. In order to address such a drawback, a conventional optical transmitter includes a resistor having a fixed resistance value that matches with an impedance of the laser diode.
However, the laser diode has a non-linear characteristic when subjected to a temperature variation. Thus, when an ambient temperature of the optical transmitter varies, the impedance of the laser diode may be non-linearly changed. In this case, an impedance matching operation may not be accurately performed. This may degrade a noise characteristic and a gain, such that optical signal transmission is poorly influenced.
The optical receiver is coupled to a photoelectric diode for converting an optical signal into an electrical signal, and includes a trans-impedance amplifier for amplifying the electrical signal and a limiting amplifier for limiting an amplitude of an output signal. The trans-impedance amplifier of the optical receiver has a single-ended structure in which an input terminal thereof is connected to the photoelectric diode.
Thus, the optical receiver may also be vulnerable to a supply voltage fluctuation, a substrate noise, or the like. In order to address such a drawback, a conventional optical receiver includes an RC passive filter installed between the trans-impedance amplifier and the limiting amplifier. The RC passive filter serves to filter noise and hold an opposite input voltage. However, since the RC passive filter of the conventional optical receiver should have a large time constant for a stable operation, a chip area occupied by the optical receiver is inevitably increased and a response time is increased.